ML090930099

Final Status Survey Summary Report for November 3, 2008, Spent Fuel Pool North Wall, (+) 0' El. to (+) 40' El., Survey Unit F8120004

ML090930099
Person / Time
Site:	Rancho Seco
Issue date:	11/03/2008
From:	Donna Anderson Sacramento Municipal Utility District (SMUD)
To:	NRC/FSME
Shared Package
ML090830613	List: ML090830313 ML090830314 ML090830316 ML090830318 ML090830319 ML090830320 ML090830321 ML090830322 ML090830323 ML090830324 ML090830541 ML090830542 ML090830543 ML090830544 ML090830545 ML090830546 ML090830547 ML090830548 ML090830573 ML090850549 ML090850550 ML090850551 ML090850552 ML090850553 ML090850554 ML090850555 ML090850556 ML090850557 ML090850558 ML090850559 ML090850560 ML090850561 ML090850562 ML090890534 ML090890535 ML090890536 ML090890537 ML090890539 ML090890584 ML090890585 ML090890586 ML090890587 ML090890588 ML090890727 ML090900729 ML090900730 ML090900731 ML090900732 ML090900733 ML090900770 ... further results
References
DPG 09-097
Download: ML090930099 (50)

Text

Rancho Seco Final Status Survey Summary Report November 3, 2008 Spent Fuel Pool North Wall, (+) 0' El. to (+)'40' El.

Survey Unit F8120004 Prepared By: cC/..- Date: /I/3//0l:

FSS Engineer Reviewed By: ate: $ t-(

Lead FSS Engineer

.. 7 Approved By: _- C d( Date:_ ______

Dismantlement Radiological

FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8120004, Spent Fuel Pool North Wall, (+)0' El. to (+) 40' El.

Survey Unit

Description:

Operating History: The reinforced concrete structure contained the spent fuel pool and supporting systems. The building contained three main elevations including the pool.

Residual radioactive material was known to be present on all levels of the interior of the building. Operating records and the HSA document several events with the potential for a release of radioactivity inside this structure. Three documented instances of contamination through the common fuel building/turbine building wall were noted.

Site Characterization: Direct measurements were made of each of the interior elevation surfaces as well as the exterior surfaces of the structure. These measurements confirmed the presence of plant-derived radionuclides. Direct measurements on the pool elevation showed a mean gross activity level of 16,900,000 dpm/100 cm 2 and a maximum value of 200,000,000 dpm/100 cm 2 . Direct measurements on the +40' elevation showed a mean gross activity level of 5,942 dpm/100 cm 2 and a maximum value of 19,357 dpm!100 cm2 .

Direct measurements on the building exterior showed a mean gross activity level of 1,408 dpm/100 cm 2 and a maximum value of 21,600 dpm/100 cm 2 . Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior of the spent fuel building was determined to be a Class 1, 2 area and the exterior was a Class 2, 3.

HSA Events: HSA Report pg. 63.

Survey Unit Design Information:

The Survey Unit Design Parameters are presented in Table 1 below. The survey unit and measurement locations are depicted on the maps in Attachment 1. Direct measurement locations were determined using a random-start, fixed grid pattern and 267.02 m 2 were scanned for 100% coverage. Samples of removable contamination were collected at each direct measurement location. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.

Page 2 of 9 FSS Summary Report F8120004

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F812 Spent Fuel Pool North Wall Survey Unit: 0004 Structure Surface Class: 1 LTP Table 5-4 SU Area (m2): 267.02 Evaluator: D. Anderson DCGL (dprn/100 cm 2 ): 43,000 Gross Activity DCGL Area Factor: 3.5 Class I Design DCGLemc 154,800 Class 1 2

(dpm/ 100 cm ):

LBGR 2 (dpm/100 cm ): 21,500 Default = 50% DCGL Design Sigma 2 (dpm/100 cm ): 12,246 Type I Error: 0.05 Type II Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m2): 6.85 Class 1 Scan Area 2 (M ): 267.02 Scan Coverage (%): 100% Class 1 1.645 1.645 Sign P: 0.955435 Calculated Relative Shift: 1.7 Relative Shift Used: 1.7 Uses 3.0 if Relative Shift is

>3 N-Value: 14 Design N-Value + 20%: 17 NUREG-1575 Table 5-5 Design Min Samples N: 39 Class 1 Grid Spacing L: 2.61 Class 1 Page 3 of 9 FSS Summary Report F8120004

Survey Results:

A total of 43 direct measurements were made in F8120004. The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. Two of the ISOCS gamma scan measurements indicated areas of elevated activity. The gamma activity ranged from < 1,550 dpm/100 cm2 to 109,801 dprn!100 cm 2 Co-60 and 1,532 dpm/100 cm2 to 72,375 dpm/100 cm 2 Cs-137. The scan grids indicating elevated activity were remediated and resurveyed. Residual radioactivity levels following remediation ranged from < 1,550 dpm/100 cm2 to 6,305 dpm/100 cm2 Co-60 and 1,532 dpm/100 cm2 to 61,089 dpm/100 cm2 Cs-137. Beta scan activity ranged from 4,154 to 226,127 dpm/100 cm 2 , based on a surveyor efficiency of 0.5 and no background subtracted. Samples for removable surface activity were all less than 10% of the DCGL as shown in Table 3. Removable surface activity samples were counted for alpha activity and none was detected at the MDC shown in Table 2-1 of Attachment 2.

Page 4 of 9 FSS Summary Report F8120004

Table 2. Direct Measurement Results Measurement ID Gross Activit)/

(dpm/100 cm F8120004-CO001BD 1,447 F8120004-CO002BD 1,468 F8120004-CO003BD 1,712 F8120004-CO004BD 1,629 F8120004-CO005BD 1,748 F8120004-CO006BD 1,722 F8120004-CO007BD 1,733 F8120004-CO008BD 1,847 F8120004-CO009BD 1,509 F8120004-CO01OBD 1,738 F8120004-CO011 BD 6,557 F8120004-CO012BD 1,961 F8120004-CO013BD 2,837 F8120004-CO014BD 2,080 F8120004-CO01 5BD 1,634 F8120004-CO016BD 1,618 F8120004-CO017BD 1,893 F8120004-CO01 8BD 2,505 F8120004-CO019BD 4,700 F8120004-CO02OBD 33,624 F8120004-CO021 BD 2,630 F8120004-CO022BD 1,790 F8120004-CO023BD 1,847 F8120004-CO024BD 1,764 F8120004-CO025BD 1,582 F8120004-CO026BD 2,033 F8120004-CO027BD 2,563 F8120004-CO028BD 5,545 F8120004-CO029BD 1,738 F8120004-CO03OBD 1,556 F8120004-C0031 BD 2,417 F8120004-CO032BD 1,686 F8120004-CO033BD 1,774 F8120004-CO034BD 2,796 F8120004-CO035BD 4,617 F8120004-CO036BD 1,971 F8120004-CO037BD 2,049 F8120004-CO038BD 1,665 F8120004-CO039BD 1,629 F8120004-CO04OBD 2,065 F8120004-C0041 BD 1,904 F8120004-C0042BD 1,883 F8120004-CO043BD 2,417 Mean: 2,974 Median: 1,847 Standard Deviation: 4,909 Range: 1,447 - 33,624 Page 5 of 9 FSS Summary Report F8120004

Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity I (dpm/100 cm 2)

F8120004C0001SM 4.22 F8120004C0002SM 0.34 F8120004C0003SM -2.24 F8120004C0004SM -2.24 F8120004C0005SM 0.34 F8120004C0006SM -0.95 F8120004C0007SM 0.34 F8120004C0008SM 2.93 F8120004C0009SM -3.53 F8120004C0010SM -3.53 F8120004CO01ISM 1.64 F8120004C001 2SM -3.53 F8120004C0013SM 5.51 F8120004C0014SM -3.53 F8120004C0015SM -2.24 F8120004C0016SM 10.68 F8120004C0017SM -4.82 F8120004C0018SM 1.64 F8120004C0019SM -0.95 F8120004C0020SM 14.55 F8120004C0021 SM 0.34 F8120004C0022SM -3.53 F8120004C0023SM 0.34 F8120004C0024SM 13.26 F8120004C0025SM -0.95 F8120004C0026SM 0.34 F8120004C0027SM 0.34 F8120004C0028SM 1.64 F8120004C0029SM 1.64 F8120004C0030SM -3.53 F8120004C0031 SM 24.88 F8120004C0032SM -0.95 F8120004C0033SM 1.64 F8120004C0034SM -0.95 F8120004C0035SM 0.34 F8120004C0036SM -0.95 F8120004C0037SM -0.95 F8120004C0038SM -2.24 F8120004C0039SM 0.34 F8120004C0040SM -0.95 F8120004C0041 SM 2.93 F8120004C0042SM 0.34 F8120004C0043SM 4.22 Mean: 1.22 Median: 0.34 Standard Deviation: 5.52 Range: -4.82 to 24.88 Page 6 of 9 FSS Summary Report F8120004

Survey Unit Data Assessment:

The survey design required 43 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 4. The sample mean and median values were less than the DCGL. The sample standard deviation was less than the design standard deviation so no additional samples were required.

Page 7 of 9 FSS Summary Report F8120004

Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2): N/A Ambient Background Used (dpm/100 can 2): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 43 Median (dpm/100 cm 2): 1,847 Mean. (dpm/100 cm 2): 2,974 Direct Measurement Standard Deviation 4,909 2

(dpm/100 cm ):

Total Standard Deviation (dpm/100 cm 2): 4,909 Based on samples and backgrounds.

Maximum (dpm/100 cm 2): 33,624 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 43 S+ Value: 43 Critical Value: 27 Sufficient Samples Collected: Yes Maximum Value < DCGL: Yes Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class 1 Total Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Yes Does the Survey Unit Pass All Criteria? Yes Page 8 of 9 FSS Summary Report F8120004

Survey Unit Investigations and Results:

Two investigations (scan grids 84 and 85) were required for the scan measurements and the results are reported in Attachment 3. The EMC unity rule was not exceeded as shown in Table 3-1.

ALARA Statement:

As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL (i.e. the survey unit average activity is less than the DCGL and the EMC criterion has been met), the ALARA criterion has been met.

Changes in Initial Survey Unit Assumptions:

The survey unit was designed as a Class 1 structure survey and the sample results are consistent with that classification. The variability of the survey results was less than the characterization data used for survey design. Two potential areas of elevated activity were detected, remediated and evaluated as shown in Attachment 3. Therefore the EMC criterion was met.

==

Conclusion:==

The FSS of this survey unit was properly designed as a Class 1 survey based on Table 5-4 of the LTP. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. No direct measurements exceeded the DCGL of 43,000 dpm/100 cm 2 and none of the removable surface activity measurements exceeded 10% of the DCGL. Two investigations were required.

The direct measurement data support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and that the data quality objectives were met.

It is concluded that survey unit F8120004 meets the release criteria of 10CFR20.1402.

Page 9 of 9 FSS Summary Report F8120004

Attachment 1 Maps November 3, 2008 Survey Unit F8120004

Attachment 1 Maps November 3, 2008 Survey Unit F8120004

41 0

0 0m 0 "

Lii Location of Fuel Storage Building inside the Industrial Area 00 A

Map F8120004-1, Spent Fuel Pool North Wall S Location of Fuel Storage Building at Rancho Seco site F'

3.81 mn 0.457 m 6.4 m 6.4 m El. 40'.0" 3.81 m 0.457 m-- °,,,

0.61 m 2 E

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---

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l.dim

---

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---

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__w 4.27 m ---- - - - - - - - - -!I-- - - -- - -ft - - - -- - i. - -

--- -- --- t;

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-- --- --I ---

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----------- 7 ---------------

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I--------------------------

JJ -- ',-----------------

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4- - ---------1 E. 00"_._'_.

10.67 m 0.0 0.5 1.0 1.5 2.0 Distance in Meters Map F8120004-2, Spent Fuel Pool North Wall Area Estimate: 94.0 sq. meters Note: Wall Area in blue not included in area estimate.

Refer to Map F8120004-4.

Page 3 of 32 Att. I Maps -F8120004

0.0 1.0 2.0 3.0 4.0 Distance In Meters Map F8120004-3, Spent Fuel Pool North Wall Page 4 of 32 Att. 1 Maps F8120004

3,81 m El. 40' 0" -

0.61 me I

---i------;ii

.. .. . 1'- -.

N i I * - -- -- - -- -- --

N) 2 Shelf at El. 15' 0"

--- --------------------- L

---

E El.5' 0" 11!

---

1-------

3.81 m 4.

3D 2 N 0.0 0.5 1,0 1.5 2.0 Distance in Meters 3.81 m Map F8120004-4, Spent Fuel Pool North Wall Area Estimate: 60.0 sq. meters Note: Area in gray not included in survey unit.

Refer to Final Survey Package F8120005.

Page 5 of 32 Att. I Maps F8120004

-- vs.

Map F8120004-5, Spent Fuel Pool North Wall Note: Area in gray not included in survey unit.

Refer to Final Survey Package F8120005.

Page 6 of 32 Att. I Maps F8120004

5.41 m El. 40' 0" E

C\

I 1- - - - - - - -- - -

CD 2

El. 15'0" 3.81 m Ell-111 E

U') r4jn.

1.6m

.......................... _- El. 0' 0"

-~

t44ý: '~ s- I I I 0441 x=

~&~'"'~ j~

Map F8120004-6, Spent Fuel Pool North Wall  %

-~ 'f 12 Area Estimate: 48.54 sq. meters Note: Area in gray not included in survey unit. ----------------- - I El. -4' 6" -

Refer to Final Survey Package F8120005. 3.2 m 0.0 0,5 10 15 2.0 Distance iiMetoss Page 7 of 32 Att. I Maps F8120004

El. 40' 0"

..- Top of Wall 5.41 m To of Wall os c4

' 1.04 m E

1.98 m 0.0 0.5 1,0 1.5 2.0 Map F8120004-7, Spent Fuel Pool North Wall Distance in Meters Area Estimate: 14.5 sq. meters Page 8 of 32 Att. I Maps F8120004

H]-:- -------

0.0 1.0 2.0 3.0 4.0 Distance in Meters Map F8120004-8, Spent Fuel Pool North Wall Page 9 of 32 Att. 1 Maps F8120004

4.34 m El. 40' 0" Ledge at El. 15' 0" 1.14 m Underside of Shelf (El. 13' 0")

- - - " - - * " " " - " - - ZZZ2ZZZZ.7_ZZZZ_'_ZZ 2 -1 -----------------

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ý3 -- - - - - -' _- - - -

EL.Q. El. O'0.

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Lines 0.0 0.5 1,0 1.5 2.0 Map F8120004-9, Spent Fuel Pool North Wall Distance in Meters Area Estimate: 96.4 sq. meters Page 10 of 32 Att. I Maps F8120004

Map 0 2.0e3.0 4.0 Oistance inMeters Map F8120004-1O0, Spent Fuei Pool North Wall Page 11 of 32 Att. 1 Maps F8120004

CD 0'

r1-1 C0 9ý Map F8120004-11, Spent Fuel Pool North Wall 0 1.0 2.0 , 3.0 4.0 Distance in Meters

('D 0

0J0 uJ pa 00 125 130 135 140 145 150

Height in meters 1

10.94 __ _ __ 14B ----------

_ 13BD O~

8.33 m I

• ~ hOD 5.72m -

---

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Height in meters Elm 3.11 m -

- ----§ D S

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E1l. ;.0'

-"4 cr1 0 0 3 3 3 3 2 -' 3 0.0 0.5 1.0 1.5 2.0 Distinco In Metcrs Map F8120004-13, Spent Fuel Pool North Wall Beta Direct Measurements F8120004C0001BD to F8120004C0014BD 2.61 sq. meter grid spacing Page 14 of 32 Att. I Maps F8120004

01 COn 00 0 2 3o El. 40' 0" El. 40Q0" Height in meters

-6.36 m Ledge at El. 15'0"

---

I ---------------

1.14 m

.. _U~ndersi~de of Shelf (El. 1ITO0)

-- 3175 m Distance in meters from bac

' !,--- .-_-_-_-_---- _-_--_-.------ -- - corner 52Z '.'..'IL*..L,.'..LL__..L .'.._..__-LL2*- -- '*

-1.76 m EID6 " --- --- -- 1.14 m

25 L C I--

EL-1 -E0 0.97 m

---

- " ~El. 0'0

i----------- El.0' I

C 0 E CE it'. 3 3 oz V EE 2 0 ~ ~ 40)C (

3 5 S1 32L 0.0 0.5 1.0 1.5 2.0 Map F8120004-14, Spent Fuel Pool North Wall Dislance in Meters Beta Direct Measurements F8120004C0015BD to F8120004C0029BD 2.61 sq. meter grid spacing Page 15 of 32 Att. I Maps F8120004

- hr n flT?' I hr - I El. 40..0" Height in meters

-t095 1

BE

- - - - - - 1 1 - - - - - - - - - - - - - - - - - - - - - - - - -

---

--------- :1L I ----- ----------------- L-:

B - 8.34 m

---

---- - - -T3--BD-- --------------------- -- :J2B - 5.73 m I I

---

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---

El. 15 0"

- 3.12 m 3D

-0.51 m El. 0' 0" I

~hr~

J~~: ~h;I

• Map F8120004-15, Spent Fuel Pool North Wall  :~t~ ~.

h~

- ~,

h~~~4' Beta Direct Measurements ~ ~r-F8120004C0030BD to F8120004C0037BD  :~: ~ $

2.61 sq. meter grid spacing I~I

- - --~

--- -------------- Rl -4' F" 0.5 1.0 1.5 2.0 z E Distance in Meters Page 16 of 32 Att. I Maps F8120004

Height in meters above shelf E1.40' 0" 6.38 m

---

1ý------------

-- ----------- L ---------;

3.77 m 2 EI 7D',"",

ý Distance in meters ------------..-------..-------

---

from shelf 1.16 m ----------- corner

-D Lill! ------------- rý-,l -------- I El. 15'0" 2.37 m -

Height in meters above grade

,---_---------- --- L?22222 3.11 m z E

-b

= 0 CNJ 0.50 m 0.0 0.5 1.0 1.5 2.0 Distance in Meters Map F8120004-16, Spent Fuel Pool North Wall n- EE Beta Direct Measurements F5 9

0L F8120004C0038BD to F8120004C0043BD 2.61 sq. meter grid spacing Page 17 of 32 Att. I Maps F8120004

Height in meters I /

11.68 I-- C002GS

---

oo ---

110 A

/

,-M -- -- -- -- --iV- --

9.58 m C05GS 00,1GS /

V Vi

---

C--- - -- -- --

/ R 7.47 C0004GS C0010 GS

/ C 5.36 m(

00003GS. <ýý009GS%

/

HILK A IJ 1

I ml' A

ý",

T-77 E 3.25 m - C0002GS C0008GS n

---

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T, 7

1.14 m - C0000 GS

---

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--------- -- ------- ---11-----------------

41------ -------- I El. 0'0" t ~/\

0 3, 0.0 0.5 1.0 1.5 2.0 Distance in Meters Map F8120004-17, Spent Fuel Pool North Wall ISOCS Gamma Scan Measurements F8120004C0001 GS to F8120004C0012GS 12.57 sq. meter field of view Page 18 of 32 Att. I Maps F8120004

0 C) 0.0 1.0 2-0 3.0 4-0 Distance in Meters CI)

Map F8120004-18, Spent Fuel Pool North Wall ISOCS Gamma Scan Measurements F8120004C0013GS to F8120004C0014GS 1 m concrete dpm PI1

• Y'[--*

--- ... ..... ab°Vr*lcOve

-3 0 C009----2GS6.79 m C0018G 4060 El.1G

-=- *alcov-

• r f C0017GS ------ C0020GS 1.34 r

-."-_ _ __-I

...... / LO EL. 15'0" .,_ \

Height in meters 3.60 in- C001 6GS

-- --i-----

/ 1

---

1

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1.16 rn- C001 5GS El. 0,0",

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Centered horizontally on wall 0.0 0.5 1.0 1.5 2.0 Map F8120004-19, Spent Fuel Pool North Wall Dis ance in Meters ISOCS Gamma Scan Measurements F8120004C0015GS to F8120004C0022GS 12.57 sq. meter field of view Page 20 of 32 Att. I Maps F8120004

41 no =;- 3 3-Height 3

in meters/ -,---'--*- - D El. 40' 0" above i she 1/

6.38 m 00COO,9GS C0026GS

\

- ------ 0---- ----

3.7m-- --

347 mn -----

I COO/

G II

-C00 5GS Height 1.50 mn in' eters ab ve gra~e

- 4.95 rnm L/'!I', ......................... j ............ l. 15' 0"

ýCOO23GS 1.61-m

- -El. 0 0" Map F8120004-20, Spent Fuel Pool North Wall * '"-1 iSOCS Gamma Scan Measurements F8120004C0023GS to F8120004C0029GS 12.57 sq. meter field of view z E 0.0 0.0 1.0 1.5 2.0 CO Distance in Meters 0 C0 Page 21 of 32 Att. I Maps F8120004

~I&

El. -46'6"~ *'£::* ** tJ * *..........

EMap F8120004-21, Spent Fuel Pool North Wall zE E ISOCS Gamma Scan Measurements E oE8 l C, F8120004C0030GS to F8120004C0042GS F .S ! M 12.57 sq. meter field of view Page 22 of 32 Att. I Maps F8120004

t'J,

,*,* ' 0.0 .0 2.0 3.0 4.0

,* Distance in Meters 44 c Map F8120004-22, Spent Fuel Pool North Wall ISOCS Gamma Scan Measurement

~Fg120004C0043GS 1 m concrete dpm O~

Height in meters 9.80 m CD U) CD UM UN 8.30 m 6.80 m 4.05 m 1.55 E!. .O:,o.

a) CO Map F8120004-23, Spent Fuel Pool North Wall

5. 't " ISOCS Gamma Scan Measurements F8120004C0044GS to F8120004C0045GS 12.57 sq. meter field of view 0.0 0.5 1.0 1.5 Distance in Meters 2.0 F8120004C0046GS to F8120004C0052GS and F8120004C0086GS to F8120004C0089GS 3 sq. meter field of view Page 24 of 32 Att. I Maps F8120004

IVI&YJFO I eUUL'.*-4/-t, OptI IL rr-U l i-UUI INOI LI VV ISOCS Gamma Scan Measurements F8120004C0053GS to F8120004C0058GS Page 25 of 32 Att. I Maps F8120004

Map F8120004-25, Spent Fuel Pool North Wall ISOCS Gamma Scan Measurements F81 20004C0059GS to F81 20004C0064GS Page 26 of 32 Att. 1 Maps F8120004

Map F8120004-26, Spent Fuel Pool North Wall ISOCS Gamma Scan Measurements F8120004C0065GS to F8120004C0067GS Page 27 of 32 Att. 1 Maps F8120004

00 0 - - - - - -

C0085GS Ii99 GOO84GS ---...-- ...----- _-_---- L--

1etert IT- --- --

]fIE]

C00813GS 3.24 m

• *fh II II I

II 0080GS C0082G 1.15mr El i4 - - *stance in meters

- from back wall -- Ieight in i eters above foor Hei, lht in heter,,

a Dove oor 1[---- L------ AN, ------ ------ -'-

3.1 n C0069GS

---

T ---

C0071GS 3.1 r H 0lr

. . . =It=---------- ----------- :

1.

1.0 n 0068GS t\

an__~ I *L,

• ml IJ I

- ---------- 11 ------------

ITJ '3 3 ,-;

00 3 3 *A*,I.%tI*A **,l,-? ** L f--..*l I'*__1 Ikl__*l,.. IAI--II Distance Distance Map -8 2000UUU4-7, Spent Fuel t-'ool N1or(( vvall 0 ISOCS Gamma Scan Measurements in meters in meters 0.0 1.0 2.0 from SW from NW F8120004C0068GS to F8120004C0083GS Distance in Meters corner corner 7.07 sq. meter field of view F8120004C0084GS to F8120004C0085GS 0.8 sq. meter field of view

0 I p cjo V)

CO006JS 00 It 0.0 1.0 2.0 3.0 4.0 Map F8120004-28, Spent Fuel Pool North Wall Distance in Meters Juncture Scan Measurements C) F8120004C0001JS to F8120004C0006JS

CJQ 0

DLII P0003BS 00 0.0 1.0 2.0 3.0 4.0 Map F8120004-29, Spent Fuel Pool North Wall Distance in Meters Penetration Beta Scan Measurements C) F8120004POO01BS to F8120004POO08BS t0

El.. 40'-.0"-

Top of Wall ---- N 5BS I 4BS I3BS I 2BS I 1BS ý X8120004C0002BD T

X8120004CO001BD (4 in. by 2 in.) (4 in. by 4 in.)

Map F81 20004-30, Spent Fuel Pool NorthWall Beta Scan Measurements 0.0 0.5 1.0 1.5 2.0 F8120004C0001 BS to F8120004C0005BS Distance in Meters Investigation Beta Measurements X8120004C0001 BD to X8120004C0002BD Page 31 of 32 Att. I Maps F8120004

X8120004M0001BD 0

wj X81 20004 MOO02BD

_1L

=%

itO . . . . . . . . . . . . .

--E------- --i[

-Il 00 0'

C)

Map F8120004-31, Spent Fuel Pool North Wall 0.0 1.0 2.0 Investigation Beta Measurements on metal Distance in Meters surrounding pulley boxes.

X8120004M0001 BD to 2 F8120004M0002BD 2

Area of metal: 598 in , 0.386 m

Attachment 2 Instrumentation November 3, 2008 Survey Unit F8120004

Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cm2 ) (dpm/100 cm2 )

M2350; 1'80733 43-98B; 148638 1,400 2,520 M2350; 203486 43-68B; 161400 433 1,033 M2350; 175834 43-68B; 148634 433 1,033 M2350; 189089 43-68B; 148460 433 1,033 M2350; 175834 43-116-1B; 1906421 491 739 M2350; 175834 43-116-1B; 1906422 796 3,258 M2350; 180738 43-51B; 1906663 1,049 2,044 Tennelec; 0401171 N/A 5.88 dpm t, N/A

_ennelec;_0401_7 N/A 11.71 dpm_13

'For concrete junctures 2

For concrete penetrations 3

For Co-60 on metal surfaces Detector Detector Model No. Serial No.

Concrete - 901 dpm/100 cm2 Cs-137, ISOCS N/A 1983920 Concrete - 1,550 dpm/100 cm 2 Co-60 Concrete - 1,040 dpm/100 cm 22Cs-137, ISOCS N/A 2983947 Concrete- 1,050 dpm/100 cm Co-60 Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2 )

Investigation Criteria - Direct 154,800 Investigation Criteria- Scan 63,300 Cs-137 (ISOCS average activity - 12.6 20,000 Co-60 sq. meter field of view)

Investigation Criteria - Scan 115,000 Cs-137 (ISOCS average activity -7.1 40,000 Co-60 sq. meter field of view)

Investigation Criteria- Scan 180,000 Cs137 (ISOCS average activity - 3.1 60,000 Co-60 sq. meter field of view)

DCGLw 43,000 DCGLEMC 154,800 Page 2 of 2 Att. 2 Instrumentation F8120)004

Attachment 3 Investigation November 3, 2008 Survey Unit F8120004

Table 3-1 Survey Unit Investigation Area ISOCS Factor ISOCS nitialValuen nlsoes Elevated for I M 2 Investigation DCGLern Grid - Level (dpm/l 00 Result Area (m 2) at DCGLemc Result 2) Unity Grimd)

Leve of edge field (dpm/lOOcm Fraction cm2 ) of view 84' Cs-137: 186,000 Cs-137:69,664 N/A 1.285 13.8 209,000 Cs-137: 14,030 0.0 Co-60: 60,000 Co-60: 54,413 Co-60: 5,878 851 Cs-137: 186,000 Cs-137: 72,375 N/A 1.285 13.8 209,000 Cs-137: 14,791 0.0 Co-60: 60,000 Co-60: 109,801 . Co-60: 6,305 nIn, Investigation TElevated Area Investigation DCGLemc Grid Investigation Initial Value Result Area (m2) Factor DCGLemc Result Unity Level (cpm)

Grid (cpm) (cpm) (dpm/1 OOcm 2) Fraction 84 & 852 3,862 N/A 8,975 0.386 33.1 529,760 254,393 0.48 DCGL SU Mean =

Survey Unit Remainder 43,000 2,974 0.07 EMC Unity Sum 0.55 1The above grids were initially greater than the ISOCS Investigation Level. The initial ISOCS measurements resulted in the decision to.perform additional remediation. The ISOCS investigation results above represent the residual radioactivity levels after additional remediation.

2Based on Co-60 efficiency for metal surfaces.

Page 2 of 2 Att. 3 Investigation F8120004

Attachment 4 Data Assessment

.November 3, 2008 Survey Unit F8120004

F8120004 Gross Activity Sample Results Quantile Plot o DCGL 43000 dpm/1 00cm-30,0 25,000nti1 2 Det0e-e 4,002 0608 .... 7 50th P 0 t f4.

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-t F8120004 Gross Activity Sample Results Scatter Plot DCGL = 43000 dpmIlOOcm1 40000 35000 CD e4 30000 E 25000 20000 0o 00 1 17700 00

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0C F8120004 Gross Activity Frequency Plot 2

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